Field of the Invention
The present invention relates to a system and a method for controlling valve timing of a continuous variable valve duration engine. More particularly, to a system and a method for controlling valve timing of a continuous variable valve duration engine that simultaneously controls duration and timing of the continuous variable valve by mounting a continuous variable valve duration device on an intake and mounting a continuous variable valve duration device and a continuous variable valve timing device on an exhaust in a turbo engine.
Description of Related Art
An internal combustion engine combusts mixed gas in which fuel and air are mixed at a predetermined ratio through a set ignition mode to generate power by using explosion pressure.
In this case, a camshaft is driven by a timing belt connected with a crankshaft that converts linear motion of a cylinder by the explosion pressure into rotating motion to actuate an intake valve and an exhaust valve, and while the intake valve is opened, air is suctioned into a combustion chamber, and while an exhaust valve is opened, gas which is combusted in the combustion chamber is exhausted.
In the operations of the intake valve and the exhaust valve, only when a valve lift and a valve opening/closing time (timing) are controlled according to a rotational speed or load of an engine can optimal engine performance be secured. Therefore, a continuous variable valve duration (CVVD) device controlling an opening time of an intake valve and an exhaust valve of the engine and a continuous variable valve timing (CVVT) device controlling opening and closing timing of the intake valve and the exhaust valve of the engine have been developed.
The CVVD device adjusts duration of the valve. In addition, the CVVT device advances or retards opening and closing timing of the valve in a state in which the duration of the valve is fixed. In other words, when the opening timing of the valve is determined, the closing timing is automatically determined according to the duration of the valve.
However, in a case of combusting the CVVD device and the CVVT device, duration and timing of the valve should be simultaneously controlled.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.